"The search for yield is going to be even more challenging," Rebecca Patterson, chief investment officer at Bessemer Trust, tells The Journal.

She’s worried about developments such as junk bonds being issued with weaker safeguards for investors. "Risk is building behind the scenes."

But the Fed’s plan to keep interest rates near record lows until unemployment shrinks to 6.5 percent just emboldens investors to buy risky assets.

Those opting for junk bonds could be singing the blues this year, says Martin Fridson, a veteran junk bond analyst who is now CEO of financial research firm FridsonVision.

“The high-yield market is extremely overvalued, by our analysis,” he wrote in a recent commentary obtained by Barron’s. “Based on the consensus forecast of a rise in Treasury yields, the expected 2013 total return on high-yield bonds is below zero.”